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Finding the Fourth Proportional to 70.28, 105.40 and 39.84

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Solution

The fourth proportional to 70.28, 105.40 and 39.84 is: 59.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    70.28 : 105.40 = 39.84 : x
  2. Step 2: Convert to fraction form
    70.28/105.40 = 39.84/x
  3. Step 3: Cross multiply
    70.28x = 105.40 × 39.84
  4. Step 4: Simplify right side
    70.28x = 4,199.14
  5. Step 5: Solve for x
    x = 4,199.14/70.28
  6. Step 6: Final answer
    x = 59.75

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.